Texans inside linebacker Brian Cushing gets treatment on the field Monday night after an injury, which turned out to be a torn ACL. / By Andrew Mills, The Star-Ledger

by Robert Klemko, USA TODAY Sports

by Robert Klemko, USA TODAY Sports

Linebacker Brian Cushing, an integral part of the undefeated Houston Texans, has a torn ACL and will be out for the rest of the season.

Cushing's left knee was injured when he was cut-blocked by an opposing offensive lineman during the Texans' 23-17 victory vs. the New York Jets on Monday night.

He left the game and did not return, and a Tuesday MRI confirmed the worst fears of every Texans fan, head coach Gary Kubiak said Tuesday.

The second-quarter downfield cut block by Jets left guard Matt Slauson was decried in NFL circles, most notably by Packers linebacker Clay Matthews, who believes the NFL has a double standard for offensive and defensive players in terms of player safety.

Cushing has 29 tackles, an interception and a forced fumble on the season, and he has been described by coach Wade Phillips as perhaps the most important member of the Texans defense.

After five weeks of the 2012 season, the Texans have allowed the fourth-fewest yards passing and the ninth-fewest receiving.

"I got cut. I got cut on a run play. It happens," Cushing said Monday night when asked if he was aware what had happened. "I was just keeping my head up. Whatever happens, happens. It's football. It's part of the game."

A part that made a few folks angry.

"Yeah, well, I would be too if it would've happened to someone else," Cushing said. "But it happened to me, and I've been on the other side of that, so I know how it goes."

Cushing's teammates weren't so understanding.

"I mean, they protect the offense. That's kind of what they do," said defensive end J.J. Watt, who had another monster game with a key sack in the fourth quarter, a tip that led to an interception and another batted ball to save a touchdown. "It's a tough situation. I mean, I understand. Football's a rough game, and I haven't seen the play so I can't comment on the play. But it's a tough game.

"Hopefully it was a legal play because you hate illegal plays, especially when players are injured. That's not what you want."

It apparently was a legal play. The question that's been asked in the past and will be asked moving forward, especially in light of Cushing's injury, is whether it should be legal. Slauson and Cushing were within 3 yards of the line of scrimmage, which is the designated area in which linemen can go low to block a player.